Process of treating slimes.



UNITED srn rns ATENT Orrion.

PROCESS OF l'REATING SLIMES.

No. scenic.

Specification of Letters Patent.

Patented Oct. 2, 1906;

Application filed March 19, 1906. Serial No. 306,911.

To all whom it may concern.-

Be it known that we, HARRY N. THOMSON and Fnnnnnrox Lnrsr, citizens of the United States, residing at Anaconda, in the county of Deerlodge and State of Montana, have invented certain new and useful Improvements in Processes of Treating Slimes, of which the following is a specification.

Our invention has relation to improvements in processes of treating slimes of sulfid ores of copper, (with or without an admixture of silver and it consists in the novel series of steps more fully set forth in the specification and pointed out in the claims.

The object of ,our invention is to effect the recovery of the metal from copper-sulfid ores (having an essentially silicious gangue) on a commercially economic basis, the process brilwing into re uisition chemical reagents Willll may be c ieaply reduced or whose cost is but nominal or w 'ch are evolved as by-preducts in the course of subjecting sulfid ores to roastingoperations.

A further object is to subject such slimes to a series of successive treatments which will result in the production of a minimum quantity of by-products and which are accompanied by, a minimum amount of waste.

The advantages of the process will be better apparent from a detailed description of' the invention, which is as follows:

The slimes here treated are those derived from ore-dressing apparatus operating on crushed 'sulfid ores not previously roasted; These slimes,which in the case of copper Ores carry more or less silver and some iron, (all the metals being in the'form'of sulfids,) are under our process first dried to thoroughly expel the water, then subsequently disintegrated, after which they are roasted at a barely dull-red heat, these series of steps be ing all accomplished in any available forms of apparatus and furnaces known to the art and familiar to the skilled metal] urgist. The roasting at a low heat (dull red) is an important consideration, since high temperatures, or temperatures above dullred, tend to render the copper insoluble for the subse quent stages of the process. The slimes before the roasting operation may be considered as a mixture of copper, silver, and iron suliids, expressed by the-chemical formula, Cu S, FeS Ag S. During the roastin oper ation a portion of the sulfur is oxidize assing off in the form of sulfur diexid, (S0,,fand

another portion of the sulfids are converted into sulfates according to the following reactions:

(In-:S-l- .ZFeSH- 150 I SZGu 0+ FQ2()3+ 55502. outs+ rest r 120 eousot+reso Ages-{-30 i AgaOd-SW. AgzS-l-(L AgzSOa' The roasted slimes (containing, as above indicated, variable mixtures of the oxids and sulfates of copper, iron, and silver)'are agitated for a period of fr om ene to two hours in. a solution comprising a mixture of sulfuric acid, ferrous sulfate, and sodium chlorid, the proportions of this mixture being from two to six parts, by Weight, of sulfuric acid, from five to twenty-five parts, by Weight, of ferrous sulfate, and from five to twenty-five parts, by weight, of sodium chloride The agitation should continue preferably at a tem perate heat (though ranging between 10 to 100 centigrade) and for a time suliicient to effect the conversion of all the copper -oxid into soluble sulfate by the action of the sulfuric acid, tl1() S()dlLl1I1 chlorid (which should always be in sufficient quantities for the purpose) acting as a solvent for the silver constituents, (oxid and sulfate) as will be readily apparentfrom the following reactions:

eis osA tson mates-easel:

6AgCLNaCl+3NagSOrl-QHsO.

We need not concern. ourselves aboutthe ferric-oxid constituent, as itisnot ofsuflicient importance to be considered as an-element, there being no occasion for its recovery and it not interfering in any wise with the subsequent steps of the process. Eliminating from consideration the ferric oxid, (Fe -0 the products resulting from the agitation of the roasted slimes in the mixture of sulfuric acid, ferrous sulfate, and sodium chlorid are in substance (as seen from the foregoing reactions) a mixture of the solutions of copper sulfate and silver chlorid, together with ferrous sulfate, ferrous chlorid sodium sulfate, and water and perhaps an excess of sodium. chlorid and sulfuric acid. To facilitate the solutienof the copper during the agitation aforesaid, air and gases (86,) from roasting, furnaces are passed through the solution.

1 action of sulfureted hydrogen for copper.

It may be sta'ted'idpassing that thesodiumchlorid constituent of themixture not only acts as a solvent for the silver, but tends to.

and the mixed solutions subjected to the.

as. The sulfureted hydrogenhreacts with t e copper sulfate, producing insoluble copper sulfid and free sulfuric acid in the solution, as shown by the following reaction:

So fatas any silver may be present this will likewise be recipitated in the form of insoluble su'lfi according to the following reactions:

QAgCLNaUI-FES:AgzS+QNaCl+2HOl. The precipitated copper sulfid (mixed more orlesswlth silver sulfid) is filter-pressed,

washed, and subsequently'smelted to metalli'c cop or b any well-known reduction process. he ltrate of sulfuric acid may be brought u to proper strength by the ad( i ti'oh of ot er sulfuric acid to be used for leaching a fresh charge of slimes in the-man" ner heretofore set out and pointed out in the 3 description.

The source of the sulfureted hydrogen for effecting the precipitation of the copper is immaterial, but we prefer to generate the same by treating a low rade matte withsul furic acid. The matte is to be made by fusing an iron-pyrite (FeS ore in a reverberatory furnace with the addition of suitable fluxes, if necessary. The pyritous ore to be used maycon'tain some copper; but it is desirable to have the matte run low in copper,

since a high precent'age of the lattenretards the action of the acids. The product of the I fusion may be expressed by the following re- V res. (fused) =FeS-l-S. The FeS'tre'ated with sulfuric acid produces the sulfur ete'd' hydrogen, thus:

FBS+HQSO:FBSOL+ H28. The mixture of copgper sulfid, undccomposed iron sulfid, matte, 0., is'to be rcmelted and blown up to copper in the converters.

The sulfuric acid for the process 18 preferably made from roasting-furnaco gases by any of the standard processes.

Having described our invention, what we claim is 1. In the treatment OfSllIllGS of metallic ores, the process of roasting the slimes, then subjecting the same to the action of acids and salts mixed in suitable proportions toeffect solution ofboth the roasted and un -OXIdIZGd portions of the ore, simultaneously passing rOasting-fmnace gases through the mass, then separating the solution, and subjecting it to the action ofsulfureted hydro en. and recovering the resulting metal sul ds, substantially asset forth.

2. In the treatment of sllrnes of metallic ores, the process of drying and. disintegrating the slimes, then roasting the same at a dullred heat, then subjecting theroasted product to the action of a mixture of sulfuric acid, iron sulfate and eodlumgchlorid and simultaneously pissing through thema'ss roastingfurnace ases inthe form of air mixed sulfur dioxid' to effect the solution of the metal compounds of the roasted product, then filtering the same, then'suhi'ecting the filtrate to the action of suliurcted h drogen and recovering the resulting sulfi s; substantially as set forth.

3. In the treatment of slirn es of metallic ores, the process of drying and disintegrating the clinics, then roasting the same at a duil red heat, then. subjecting the roasted product to the action of a mixture of sulfuric acid, iron sulfate and sodium chlori'd and simultaneously passing air and sulfur-dioxid gas through the mass to effect solution of the metal compounds, then filtering the-same, washing the ceilings or residue and combining the filtrate with the wash-waters, then.

passing sulfureted hydrogen througl'i the solution, and finally recovering and; smelting the metal sulfide, substantially as set forth.

4. In the treatment of shores of copperores, the process of roastingithe slimes, subjecting the roasted product to the action of acids and salt solutions impregnated with sulfur dioxid, to effect solution of the metal of the ore, filtering the same, subjecting the filtrate to the action of sulfureted hydrogen, removirn the resulting precipitate of copper sulfid, titer-pressing, washing, and. finally smeltm the same to metallic copper, substantial y as set forth.

In testimony whereof we affix our signs, tures in presence of two witnesses.

' HARRY N. 'lHOMSUN. FREDERICK in EST.

Witnessos H. R. Buns, M. MARTIN. 

